1. Field of the Invention
The present invention relates to a multi-layer substrate which should be used with an inductor.
2. Description of Related Art
Generally, a multi-layered substrate made of dielectric obtains a large inductance by mounting an inductor on a surface of the substrate. The magnetic permeability of the multi-layer substrate is low, and therefore, a large inductance can not be obtained by providing a conductive pattern for forming a coil inside the substrate.
The inductor which is mounted on the multi-layer substrate is required to have various values of inductance. However, it is impossible to comply with all the requirements because of problems such as a manufacturing cost and a storage area. Thus, conventionally, an inductor which has the most suitable inductance is selected among several kinds (or dozens) of standard items which have predetermined values of inductance, and a circuit must be designed according to the inductance of the selected inductor.
Also, as for a circuit whose tolerance in the inductance value is narrow, an inductor whose deviation is narrow is needed to be obtained exceptionally.